many times have you heard this -- "don't go outside with your hair wet. you'll catch a cold." do you think that's true? >> yeah, i do think it's the truth. >> yes. >> why? >> because your hair's wet, and it's cold outside. >> yes. >> why? >> because i've done that before, and i got a cold. >> yeah, my hair froze once when i was coming back from swim practice. >> if you go outside with wet hair, you are inviting a bad hair day, but you're not inviting a cold. >> scientists in england found that warning just doesn't hold water. >> that's just one of the health myths checked out by realsimple.com. here are some others. gum stays in your stomach for seven years. do you believe that one? >> yes. >> why? >> 'cause it's sticky. >> no, i think you digest it. >> file this one under myth. the experts say your digestive system does dissolve gum, though it might take a few days. but don't make a habit of swallowing it. eat an apple instead. after all, "an apple a day keeps... >> the doctor away. >> and not just apples. there are all kinds of fruits that are better for us than candy and cookies.